97 Bonnie with a vibration in car.

I have posted this before but thought I would try again. Out 97 bonnie has a vibration between 70-80 and it is slowly getting worse. I can't figure out what it wrong with it. I have had the tires balenced so many times I can't remember. I even put new tires on it last year with no luck. I've had the front end checked out by several dealers and tires places etc. It gets worse the longer you drive it. Sometimes at first it don't shake at all. I'm starting to think that it is something in the transmission. If I put the car in neutral while going 75 it will still shake until it goes under 70 though so I"m lost. Does anyone have an idea what it could be? It is such a nice car and I can't afford another right now. BTW it has 127k on it now. It had 80k on it when we got it and it shook then too.
Rob

This sounds like an axle shaft going bad. The key here is that the vibration starts at a certain speed and does not continue above or below that particular speed. If it is getting worse then you need to have them checked. One thing to remember this has to be part of a rotating mass since it does it when you put it in neutral. The only things that rotate here are the wheels, tires, brakes, bearings and axle shafts. Because of the propensity of these to wear I would check the axles since you have balanced the tires repeatedly and nothing has changed.

I agree with Lynn (GTP Dad) . Another possibility is the hub bearing(s). When inspecting them, make sure you loosen the axle nut. With the axle nut loose, a bad hub bearing will be even easier to spot. Normally they will cause a hum or growling noise before they vibrate like this, but it's another thing to check if the Axle shaft checks out ok.